When an object has a file container and a user checks out the file, there is no indication on the related object that the file container is checked out. The only time a user will see anything is if they select the ellipsis on the file and the check out function is not available. However, the user does see the check in function even though someone else checked out the file.
With the new Files topic used across all objects supporting file containers, both the Files topic itself and the warning area will notify if a file has been checked out.